Software tools for Supernova Searching

There’s a plorithera of astronomy software out there for everything from the ktichen sink to photometry. I have found it hard to wade through this thick soup of software titles when trying to identify what is needed for research goals such as supernova searching.

On this page I am building up a little bit of a knowledge base of software relating to supernova searching and analysis. It is by no means claiming to be a complete reference but I find that once I start a page such as this it eveolves over the years to become something useful.

For me the decision of what piece of software often comes down to what I alrady have. Not just because of price but the associated learning curve of introducing new software to a workflow also. For this reason I have most actively tried using Astrometrica, CCDSoft and MaximDL. While I have a license for MPO Canopus I haven’t used it much.

Blinking supernova images:

  • CCDSoft provides two ways to blink images. You can load a set of pre-aligned images (presumably two in the case of supernova searching) then select Research -> Comparison -> Blink Comparitor to blink that set of images. This is useful for individual subject galaxies you wish to bilnk but painful for larger sets of multiple targets. The second way is to use the Resarch -> Analyze -> Comparative Search (Supernovas) option. This allows you to blink a set of aligned images. The catch here is you need to insert WCS (an astrometric solution via a plate solve) first and while this may be paliness for many it can be problematic for small fields of view and for the purpose of blinking two images is completely unnecessary.
  • Sehgal Observatory Supernova Search Tool (plugin for Maxim DL) is a neat little utility, probably the easiest software to use for blinking a set of supernova candiates. You select a directory of reference images, a directory of new images, and a directory to store reshoot images (possible supernova candidates PSN). The settings are remembered between use so you only need to change minimal settings each run. Alignment is automatic as is matching the images in to pairs ready for blinking. All you do is click next to move between pairs of images to blink. This does require your files are named identically (reference image “IC 1615.FIT” in one directory and new image “IC 1615.FIT” in a second directory). The only catch with this tool is you need a Maxim DL license to use it.
  • Starblinker allows you to easily search for new stars in your astronomical photos. Starblinker asks you to insert two images, your fresh image and an older, reference image. After this step, the program will search how to match the stars in the two images. The program can rotate and mirror the images, and works even if the scale or the field of the images is not the same (but they have to be not much different). Then, after few seconds, you should see the two images blinking, and this should allow you to easily search for new features in your image. You can choose the blink time, and enlarge o decrease the size of the images in the screen.

Light curve analysis of Supernova:

  • Astrometrica (uses PSF to give you a magnitude estimate for a supernova by way of you clicking on the SN star after having computed the astrometric solution of the image). I like using Astrometrica for individual images. It produces the right information what what I often am after. It’s problem seems to be in plate solving (matching the database to image) and in 99% of cases I need to manually match the image to the database star field using its fidly controls even when the mis-match is only out by a matter of 100 pixels or less and configured tollorances are much more forgiving. That being said, once plate solved, it’s great to be able to click on any point source in the image to determine it’s magnituded.
  • MPO Canopus (lightcruve generation capabilties). MPO Canopus is highly regarded and used by some institutions such as Lowell Observatory.
  • Maxim DL (lightcurve generation capabilities via it’s Photometry menu). This seems to be the easiest piece of software I own for graphing the light curve of a supernova in a large number of frames. Having reduced and aligned the frames it is quite easy to select any number of reference images, the supernova (as the “new object”) and click to generate the graph. Customisation of the aperture (MaximDL uses aperture photometry) and annulus is easy via right-clicking on the image. Note that you don’t need the full version of MaximDL to use it’s photometry tools, only the image processing version is required.
  • CCDSoft (lightcurve generation capabilities via it’s Generate Light Curve’s functionality in the Data Analysis dialog. Remember to configure your Photometry Setup via the toolbar icon). CCDSoft is not very popular for this type of work, I can only presume due to it’s relatively poor documentation and transparency. It will create a CSV of magnitude estimates for an object but exactly how it arrives at those estimates seems to be somewhat of a mystery. It uses SExtraction as the backend engine but presumably aperture photometry is used with this? If it is then how is the aperture configured, is this what the attributes in Photometry Setup do? The documentation isn’t clear and this lack of transparency makes it hard to trust the magnitude estimate results returned by CCDSoft.
  • AIP4Win (performs aperture photometry to generate a light curve). While reasonably popular I haven’t yet used this piece of software. MaximDL performs aperture photometry easily so I have been using that. API4Win does the same type of photometry (aperture based).
  • SExtractor (source extration of images, able to be configured for use in generating photometry of light sources in an astronomic image).
  • Aperture Photometry Tool.